const express = require('express')
const app = express()
app.get('/', (req, res) => {
  console.log(req.query.fn);
  const fn = req.query.fn // 字符串
  /* 返回一个函数 */
  var arr = [1, 2, 3]
  res.send(fn + '(' + JSON.stringify(arr) + ')')//fn([1,2,3])
  // res.send('111')
})
app.listen(2000, () => {
  console.log('http://127.0.0.1:2000');
})